Neuropathies Flashcards
Presentation of a polyneuropathy generally
Diffuse, symmetrical. Long axons affected first - eg. to the feet. Then progresses proximally with legs and hands being affected.
Can be progressive, relapsing or transient
Can be sensory or motor or autonomic (or mixed)
‘Glove and stocking’ but stocking first
What is a radiculopathy?
Disease affecting the nerve roots eg. root compression
What is a plexopathy?
Disease affecting the brachial or lumbosacral plexus
Sensory symptoms of large myelinated fibre disease
Loss of fine touch, vibration and joint position sense (feel like cotton wool, difficulty discriminating textures and unsteady gait)
Paresthesiae - pins and needles
Sensory symptoms of small unmyelinated fibre disease
Loss of pain and temp - therefore painless burns and trauma and Charcot’s joints
Painful positive symptoms - burning sensations, dysaesthesia, hyperalgeisa, allodynia
Motor symptoms of neuropathy
Weakness - usually distal - clearing the kerb or opening jam jars
But can be proximal - climbing stairs and combing hair
What causes median nerve compression
Carpal Tunnel syndrome - entrapment at the wrist in the carpal tunnel
Symptoms of CTS
Tingling, pain and numbness in the hand
Waking at night and relieved by shaking over the side of the bed “wake and shake”
May extend up the arm
Wasting of thenar eminence if chronic
Tests to confirm CTS
Tinel’s Sign - taping the wrist over the nerve will may the pain/tingling worse and can give electric shock feeling
Phalen’s test positive - flex wrists and press against each other for 60seconds - tingling and numbness
Causes/associations of CTS
Idiopathic, hypothyroidism, 3rd trimester pregnancy (oedema), RA, acromegaly, sarcoid, neoplasms and benign tumours eg. lipomas
Treatment of CTS
Splint worn at night
Steroid injections locally
Surgical decompression
What causes ulnar nerve compression, what are signs and what is treatment?
Cubital tunnel damage - at elbow - elbow fracture
Or Guyon’s canal at wrist (no sensory symptoms) - handlebar palsy
Clawing of the hand - wasting of interossei and hypothenar muscles
Sensory loss - little finger and half of ring finger
Treatment with decompression and transposition (at elbow)
What causes radial nerve compression and what are the signs?
Compression against the humerus - eg. hanging arm over the back of the sofa
Causes wrist drop, weakness of brachioradialis and finger extensors
Sensory loss in the anatomical snuffbox
What is the name of lateral cutaneous nerve of the thigh compression, what happens and what are signs?
Meralgia paraesthesia
Entrapment under inguinal ligament
Causes burning, tingling and numbness of anterolateral surface of the thigh
Usually occurs in overweight people therefore lose weight
How do you get common peroneal nerve palsy? What does it cause?
Damage as winds around the fibular head - eg. cast, trauma, sitting cross-legged
Signs = foot drop, weak ankle dorsiflexion/eversion, sensory loss over dorsum of the foot and lateral calf
What causes damage to sciatic nerve and what are symptoms?
Fracture of femur or pelvis or pelvic tumours
Affects hamstrings and all muscles below the knee and loss of sensation below the knee laterally
What is mono-neuritis multiplex?
2 of more peripheral nerves are affected by neuropathy
Causes of mono-neuritis multiplex?
WARDS PLC
Wegeners AIDS/amyloid RA DM Sarcoid
PAN
Leprosy
Carcinomas
What is Guillan-Barre Syndrome?
Postinfective polyneuropathy
Inflammatory demyelinating polyradiculoneuropathy
Prevalence of GBS world-wide annual rate
3/100,000
What usually precipitates GBS?
Often follows 1-3 weeks after resp or GIT infection
Can also be associated with CMV
Pathology of GBS
Infecting organisms antibody responses against peripheral nerves - possible molecular mimicry
Symptoms of GBS
Weakness of distal limb muscles
Distal numbness
Progresses proximally over period of time
Loss of tendon reflexes
20% progress to respiratory failure and facial muscles also affected
Can get autonomic features
Diagnosis of GBS
Clinical
Nerve conduction studies
CSF protein often raised
What is Miller-Fisher Syndrome?
Type of GBS with ocular muscle palsies and ataxia
Antibodies against GQ1b - ganglioside in 90%
Management of GBS
Ventilation if resp failure - thromboprophylaxis
If within 2 weeks - immunoglobulin
What is Chronic Inflammatory Demyelinating Polyradiculoneuropathy?
Syndrome similar to GBS but with more prolonged onset and recovery
Rarely associated with preceding infection
Long-term immunosuppression with steroids or immunoglobulin
How many diabetic patients get neuropathy
50% after 20 years - associated with poor glycaemic control
Different types occur - can be sensory/motor/autonomic
If autonomic get gastroparesis
Neuropathy in renal disease?
Chronic renal failure with uraemia causes progressive sensorimotor neuropathy
Response to dialysis is variable but renal transplant is curative usually
What thyroid disease causes neuropathy
Both hypo and hyper
What neuropathy is associated with porphyria?
Predominantly MOTOR neuropathy - mainly proximal
Paraneoplastic polyneuropathy
Malignant disease (esp. small cell carcinoma of bronchus) can cause sensory neuropathy and ataxia
Associated with anti-Hu/anti-neuronal antibodies
Can pre-date appearance of malignancy by months or years
Neuropathy in amyloidosis
Predominantly sensory, painful neuropathy - distortion caused by deposition of amyloid around vessels in the nerves
Autonomic features are common
Neuropathy in alcohol abuse
Up to 30% of all neuropathy cases
Slowly progressive, distal sensory loss, parasethesia, burning pains
Due to primary alcohol toxicity and also deficiency of vitamins
Also get myopathy and muscle weakness
Treatment by abstinence from alcohol, vitamin replacements
Ease pain with TCAs or gabapentin
What vitamin deficiency is caused by alcohol?
Thiamine - B1 - Deficiency
What deficiency causes sensory neuropathy when having TB treatment?
Pyridoxine B6 deficiency - therefore when taking isonizid for TB - pyridoxine is given - 10mg daily
What is Charcot-Marie-Tooth Disease?
Group of hereditary motor sensory neuropathies
Present in puberty
Distal limb wasting - peroneal muscles (reverse champagne bottles)
Loss of sensation and reflexes too
Pes cavus and toe clawing
Clinical features of radiculopathy
Pain - sharp, shooting, burning - in cutaneous distribution affected - or in the myotome
LMN signs
Sensory Loss
What do you get with lateral cervical disc protrusion?
Severe pain in the upper limb
Most commonly C6-C7 disc affecting C7 root - therefore C7 dermatome/myotome (triceps, deep to scapula and extensor aspect of forearm - pain), weakness of these muscles, sensory loss - forearm and palm into middle finger
Loss of triceps jerk (C7)
What do you get with lateral lumbar disc protrusion
L5 and S1 commonly affected
Low back pain and sciatica
Loss of sensation in dermatome
Ankle jerk lost - S1 reflex arc
Weakness of plantar flexion (S1) or great toe extension (L5)
Usually acute onset - following lifting, bending etc
What do you get with central lumbar disc protrusion
Cauda Equina
Polyradiculopathy not myelopathy (normal with central protrusions)
Lower back pain LMN weakness Areflexia Sacral numbness Urinary retention and bowel dysfunction ED
General management of radiculopathy with disc protrusion?
Analgesia and may resolve with rest
Can do decompressive surgery - urgent if central lumbar disc protrusion
Features of Erbs Palsy
Waiters tip posture - sensory loss in C5/C6 distribution
Caused by falling on shoulder or traction on neck/shoulder at birth
Features of Klumpkes Palsy
Caused by forced abduction of arm - trauma or at birth
Clawed hand - loss of intrinsic hand muscles and long flexors and extensors of fingers
Sensory loss in C8/T1 dermatomes
Horner’s syndrome
What is neuralgic amyotrophy
Severe pain in plexus (muscles of shoulder - brachial neuritis)
Followed by rapid wasting of proximal muscles (demyelinating plexopathy)
Sensory symptoms are rare
Can also occur in lumbosacral plexus
Pancoast tumour presentation
Apical lung tumour C8/T1 most common Severe pain in arm Weak and wasted hand - sensory loss Horner's syndrome
What happens in thoracic outlet syndrome from cervical rib?
Compresses lower brachial plexus roots - C8/T1 - pain, wasting and sensory loss (thenar mostly - T1)
Horners syndrome possible
Can also cause subclavian artery/vein occlusion
- Unilateral raynauds
- Loss or radial pulse on abduction and external rotation of shoulder = ADSON’s SIGN
Neurological and vascular rarely occur together
Lumbosacral plexus signs in upper plexus lesion and lower plexus lesion
Upper = weakness of hip flexion and adduction - anterior leg sensory loss
Lower = weakness of hamstrings and foot muscles - posterior leg sensory loss
What does cervical spondylosis cause?
Progressive spastic quadriparesis with sensory loss below the neck
As flex and extend the neck, drags the cord over bony spurs
Limited painful neck movement - neck flexion may produce L’Hermittes sign
Management of cervical spondylosis
Firm neck collar
Surgical root decompression
Transforaminal steroid injection - because nerve root inflammation may be causing pain
